Brake mechanism for automotive vehicles



April 21, 1931. s BRAGG ETAL 1,801,410

BRAKE MECHANISM FOR AUTOMOTIVE VEHICLES Filed Dec 12, 1927 1N1 ENT0RSATTORNE Patented Apr, 2-1, 1931 UNITED STATES PATENT OFFICE CALEB S.BRAQG, OF PALI BEAOH, FLORIDA, AND VICTOR W. KLIESRATE, OF PORT-WASHINGTON, NEW YORK, ASSIGNORS TO BRAGG KLIESRATH CORPORATION, LONG-ISLAND CITY, NEW YORK, A CORPORATION OF NEW YORK BRAKE MEORANISM FORAUTOMOTII TE VEHICLES Application filed. December 12, 1927. Serial No.239,448.

Our inventi'on consists in the novel features hereinafter described,reference being had to the accompanying drawing which shows twoembodiments of our invention 5 selected by us for purposes ofillustration, and the said invention is fully disclosed in the followingdescription and claims.

The object of our invention is to provide a brake system for a pluralitof wheels of an automotive vehicle inclu ing the steering wheels andnon-steering or traction wheels, all of which are simultaneously ap'-plied by a power actuator operated preferably by a substantiallyconstant maximum diiferential of fluid pressures, and comprising twoparts both movable with respect to the vehicle toward and from eachother and connected by a collapsible enclosing member of the bellows oraccordion type, each of said movable parts being connected with brakemechanisms for one pair of wheels only, said connections applying thepower of the actuator to the brake mechanisms of both pairs of wheels atpredetermined leverages, which will enable the maximum power of theactuator to be applied without locking the steering wheels upon theaverage dry pavement or roadway, and without locking the rear or drivingwheels upon the average dry pavement or roadway, even when the vehicleis lightly loaded, means being provided whereby the physical force ofthe operator may be added to the brake mechanisms for the rear ordriving wheels only to supplement the action of the power actuator instopping the vehicle when heavily loaded, or in making emergency stops,and to apply the brakes for the rear or driving wheels in case offailure of power, the brake mechanisms for the front or steering wheelsbeing applied only by means of the power actuator and to thevpredetermined extent provided by the connections therefrom.

In the operation of a brake system embodying our invention, the averagestop of the vehicle is effected by the power actuator alone without thepossibility of locking either the steering wheels or the driving wheelson the average pavement when dry,

and a larger pro ortion of the braking action may, there ore, beeifected by the brake mechanisms for the steering wheels than wouldotherwise be possible, and the physical force of the operator will-beap- 65 plied only for emergency stops or in case of excessive loads, andin such cases will be applied only to the brake mechanisms for the rearor driving wheels, which especially in the case of trucks or buses carrythe greater part of the load of'the vehicle and its contents, andtherefore more power is required to apply the rear wheel brakemechanisms effectively when the vehicle is heavily laden than when it islight. In the operation of a brake system embodying our invention, thevehicle may be stopped more quickly and with less danger of locking thewheels and consequent skidding even on wet pavements, and longer wear ofthe brakes W and tires will necessarily result.

We also prefer to construct the actuator cylinder so that the movementsof the mova le parts connected with the brake mechanisms toward eachother to roduce a power stroke for the application 0? the brakes will besufiicient to com ensate for normal wear of the braking sur aces withoutpermitting said movable parts to reach their limits of movement, and asthe power actuator will automatically distribute its power to the brakemechanisms for both pairs of Wheels uniformly at all times according tothe predetermined leverages in its connections therewith, without regardto the wear of the braking surfaces, the brake mechanisms ma be used forvery long periods without a justment. lVe prefer to provide an adjustingdevice in the connections between the operator operated part and thebrake mechanisms for the non-steering wheels so that the operatoroperated part, as for example the foot lever, may be prevented fromreaching its limit of movement before the brake mechanisms connectedtherewith are fully ap- 95 plied, this being the only adjusting meanswhich it may be necessary to operate, so that the brake system may beoperated for lo periods without any adjustment at all the brake liningsare worn out, and if any 199 adjustment is require it may beaccomplished by a single adju zment in the connections between the footlever and the rear wheel brake mechanisms.

Referring to the accompanying drawings,

Fig. 1 is a diagrammatic view representing an installation of brakemechanism in an automotive vehicle embodying our invention.

Fig. 2 is an enlarged detail sectional view of the power actuatorillustrated in Fig. 1.

Fig. 3 is a similar view illustrating a modification.

Fig. 4 is an enlarged sectional view of one form of valve mechanismwhich may be employed for controlling the actuator.

Referring to Figs. 1, 2 and 4, represents an internal combustion enginefor propelling the vehicle indicated diagrammatically in Fig. 1, theengine having the usual suction passage comprisin a vertical portion,61, and intake manifold, 62, for supplying the charges to the cylinderof the engine from the carburetor, 63, under the control of the usualthrottle Valve, 64, inter osed between the carburetor and the cylinc ersof the engine. The front or steering wheel brake mechanisms areindicated at F, F, and the rear or driven wheel brake mechanisms at R,R. The brake mechanisms may he of any desired type, but are shown forconvenience in this instance as comprising each a brake drum, 70, brakeband, 71, brake operating lever, 72, with. the usual retracting spring,73. The levers, 72, of the front wheel brake mechanism are connected bylinks, 74, with arms, 75, on a rock shaft, 76, secured to the chassis ofthe vehicle and provided with an actuating arm, 77. The levers, 72, ofthe rear wheel brake mechanisms are connected by links, 74, 7'4, witharms, 75, 75, with a rock shaft, 76, provided with actuating arms, 77and 77*. I

The power actuator shown in these figures is of the bellows type andcomprises two members, 1 and 3, both movable with respect to thechassis, and being hinged or pivotally connected with each other, asindicated at 2, in any desired manner, said members being movable towardand from each other and being connected by a collapsible bellows,indicated at 4, so as to form an air-tight chamber between said movablemembers, capable of being varied as to its capacity by the movements ofsaid members, 1 and 3, toward and from each other. The bellows memberIn? be provided with suitable means, as sti ening wires or frames,indicated at 6, to prevent the distortion of the bellows member by thedifi'erential or fluid pressures on its walls. The actuator ispreferably pivotally supported adjacent to the pivotal connectionbetween the members, 1 and 3, from the chassis, bracket or hanger, 7,for this purpose being incli-.

tec no cated in Fig. 2, the construction being such that the members, 1and 3 are movable pivotally with respect to each other and with respectto the bracket or hanger and supporting the bellows member. Une of themovable members of the actuator, as the member, 1, is connected adjacentto its outer end by link, 78, with the arm, 77 on the rock shaft, 76,connected with the front or steering wheel brake mechanisms, and theother the actuator, the members, 1 and 3, will be caused to move towardeach other, thereby applying both sets of brake mechanisms connectedtherewith and acting as an equalizing device to distribute the power ofthe actuator uniformly at all times between the front or steering wheelbrake mechanisms and the rear or traction wheel brake mechanisms, inaccordance with the predetermined leverages provided in the connectionbetween the actuators and said brake mechanisms, and the leverages atwhich the power of the actuator is applied to both sets of brakmechanisms is such that the front or steering wheel brake mechanisms andpreferably ,the brake mechanisms for the rear or traction wheels also,will not lock the wheels of the vehicle to which. they are applied on anordinary dry pavement or roadway. It is obvious that the particularleverages at which the power is applied to the several brake mechanismsmay be predetermined, so as to secure the desired results with theparticular type of brake mechanisms and connections e iployed.

We prefer to utilize the suction existing in the suction passage of theengine between the throttle valve and the engine cylinders when theengine is running and the throttle valve is closed or partly closed, asthe source of suction or lower fluid pressure for the operation of theactuator, and to connect the actuator with the suction passage and withthe atmosphere under the col rol of valve mechanism, which is preferablylocated in linkage between the operator operated part for the valvemechanism and the brake mechanisms for the nonsteering Wh els only. Theparticular construction of c valve mechanism forms no part of ourpresent invention and may he of any desired type. For purposes ofillustration, we have shown in Figs. 1 and 4 a type of valve mechanismwhich forms the subject r atter of o r former a plication for ters ofthe Unite States, file-d r/larch 13, and,

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'ven Serial No. 94,412, which will thereore be described onlysufliciently to enable the operation of the power actuator to beunderstood. The valve mechanism coinprises a valve casing, 10, providedwith a central valve chamber, 17, having oppositely disposed valve seatsand oppositely disposed valves, 40 and 41, controlling the communicationrespectively between said chamber and apertures, 11 and 12, provided inthe casing on opposite sides of the valve chamber. The valves, a0 and41, are preferably formed of molded rubber, cork, or other suitablematerial, and are provided with central apertures having a sealingengagement-with a hollow valve actuating sleeve, 20, which is providedwith collars, 40* and 41, on opposite sides of the said pair of valves,and said valves are *yieldingly pressed toward their seats by a spring,or springs, indicated at 50, the said'collars being so arranged that alongitudinal move,- ment of the valve actuating sleeve in eitherdirection will effect the opening of one valve after permitting theother to be closed by the spring, and to permit both valves to be seatedsimultaneously. Means are also provided for limiting the relativemovement between the valve actuating sleeve and the valve casing toprovide a limited amount of lost motion. In this instance a collar, 28,on the valve sleeve engaging an adjustable sleeve, 21, in the end 0 thevalve casing limits the movement of the sleeve, 20, in one direction,its movement in the opposite direction being limited by the engagementof a plug, 26, which closes the inner end of the valveactuatin sleevewith the threaded end or a link rod, 25, which connects the valve casingwith an operator operated part, as the foot lever, 88, provided with theusual retracting spring, 89, the valve actuating sleeve, 20, beingprovided withapertures, 27, communcating with the valve chamber, 17, andthe outer end of said sleeve is provided with a fitting, 29, having anipple, 32, communicating with the interior of the sleeve, and an ear orlug, 30, which is connected by a link rod, 79, with the arm, 77*, on therock shaft, 76 for operating the rear wheel brake mechanisms through theintervention of an adjusting device, indicated at 79*, which may be aturnbuckle or equivalent threaded adjusting means, preferably providedwith a wing nut, 79, for varying theefiective length of the rod, 79. Inthis instance the aperture, 11, in the valve casing is shown connectedby a flexible pipe, 65, with the suction passage of the engine betweenthe throttle valve and the cylinders thereof. The aperture, 12, of thevalve casing is open to the atmosphere, and the nippic, 32, on the valveactuatingsleeve is connected by a flexible pipe, 33, with a nipple, 3,on the member, 3, of the power actuator anisms when the valve mechanismis in the released or off position. The collars, 40 and 41*, are sospaced on the valve actuating sleeve that both valves may be seated atthe same time, and one valve will open after the other is closed whenthe valve actuating sleeve is moved in either direction, and the stopsprovided for the valve mechanism are so adjusted that in the releasedposition of the valve mechanism and brakemechanism illustrated in Figs.1 and 4, the retracting means for the operator operated part will holdthe valve casing in such position with respect to the sleeve, 20, thatthe suction valve, 40, will be normally maintained in closed position,while the inlet valve, 41, will be maintained in open position, therebyplacing the interior of the actuator in communcation withthe atmosphere,and ualizing pressures on the inner and outer aces of the members, 1 and3.

Assuming that the engine is running and the throttle valve is closed orpartly closed, a state of rarefaction is maintained in the suctionpassage of the engine and in the suction pipe, 65, which is preferablyprovided with a check valve, 66, opening in a direction toward thesuction passage, to prevent variations in the degree of rarefaction inthe suction passage from being transmitted to the suction pipe and tothe power actuator when connected therewith. To effect an application ofthe brake mechanisms by power, the operator will depress the foot lever,88, thereby movin the valve casing forward in the direction 0 the arrowin Fig. 4, permitting the air inlet valve, 41, to seat and cut oilcommunication between the atmosphere and the interior of the actuator,and thereby opening the suction valve, 40, to place the interior of theactuator in communication with the suction pipe, 65. The air within theactuator will be withdrawn into the suction passage of the engine, andthe difl'erential of fluid pressures on the opposite faces of themembers, 1 and 3, of the actuator will cause them to move toward eachother, thereby applying simultaneously the brake mechanisms for thesteering wheels and the non-steering wheels and distributing the powerof the actuator to said brake mechanisms uniformly at all times inaccordance with the predetermined leverages provided in the design ofsaid brake mechanisms and connections, regardless of the difierences inthe wear of the braking surfaces respectively of said brake mechanisms,the actuator operating as an equalizing means to efiect this result. Aslong as the operator continues to depress the foot pedal, the valvemechanism will move forward with the member, 3, of the actuator, towhich they are operatively connected through the crossshaft, 76, and theconnections previously described, and when the forward movement of thefoot lever ceases, the continued movement of the actuator will move thevalve actuating sleeve forward with respect to the valve casingsufiiciently to close the suction. valve, 40, without opening the inletvalve, 41, thus holding the brakes as applied. The operator will releasethe pressure on the foot pedal or remove his foot therefrom, and permitthe retracting spring, 89, to move the valve casing, 10, rearwardly withrespect to the valve actuating sleeve sufii clently to efi'ect theclosing of the suction valve and the opening of the air inlet valve,permitting atmospheric air to enter through the a rture, 12, in thevalve casing and pass into the actuator, and as the pressure within theactuator again builds up to at mospheric pressure, the members, 1 and 3,of t e actuator will move away from each other, releasing the brakemechanisms for both the steerin wheels and non-steering wheels, the footlever and the valve mechanism returning with the brake mechanisms forthe non-steering wheels to the released position indicated in Figs. 1and 4, in which said parts will be arrested by the stop, 34-. Va alsoprefer to provide an adjustable stop for limiting the extent to whichthe members, 1 and 3, of the actuator may separate thus relieving thebellows members from strain, and this may be conveniently effected byproviding an adjustable stop, 86, on a bracket, 37 secured to thechassis for engagin the arm, 77, on the rock shaft, Y6, as in icating inFig. 1, or this result may be secured in other ways.

When the brakes have been fully applied by the actuator as previouslydescribed, the operator may add his physical strength to the brakemechanisms for the non-steering wheels only, if he so desires, byfurther de pressing" the foot lever so as to take up the lost motionbetween the valve casing and. the valve actuating sleeve, and bringingthe collar, 28, into engagement with the sleeve, 21, and this isfrequently desirable for comnsating for additional loading of the vecleor in making emergency stops, and will be accomplished without in an wayincreasing the braking force applie to the front wheels. It will also beobvious that the operator by taking up this lost motion may apply therear wheel brake mechanisms by physical force alone in case of failureofpower, in which case the first part of the movement would shift thevalve mechanism into osition to vent the actuator, which woul benecessary if the link, 78, were an unyielding connection. Where thelink, 7 8, is a flexible cable, as indicated in Fig. 1, or is otherwiseconstructed so as to rovide lost motion between it and the arm, 7, theoperator may apply the rear or non-steering wheel brakes by physicalforce alone in case of failure of power without moving the actuator atall, but in either case the ph sical force of the operator can only beapplied to the brake mechanisms for the rear or non-steering wheels.

In Fig. 3, we have shown a slightly modified form of power actuatorwhich may be employed in carryin our invention into effect, and which is0 what may be termed the accordion type. In this instance the poweractuator comprises the members, 101 and 103, movable with respect to thechassis and toward and from each other, said members being substantiallyparallel and connected by a bellows like collapsible member, 104, theangular folds of which are provided. with reinforcing frames, 106, tosupport them when the air is exhausted from the interior of the actuatorto a greater or less extent. The members, 101 and 103, are movablysupported with respect to the chassis, in this instance by links, 107,which ermit the movements of the actuator memrs, 101 and 103 which inturn support the collapsible or bellows member. The member, 101, isconnected by a link, 17 8, with the brake mechanisms for the steeringwheels, and the member, 103, is connected by a link, 178*, preferably inthe form of a flexible cable, with brake mechanisms for the non-steeringwheels in the same mannor as indicated in Fig. l, and the actuator willbe connected to the valve mechanism by a flexible pipe, 133, in the samemanner as shown in that figure. The operation of the brake system isexactly the same as that hereinbefore described with reference to Figs.1, 2 and 4.

In both embodiments of our invention only one adjustment, to wit, theadjusting device, 79, located in the connection between the valvemechanism and the brake mechanisms for the rear wheel brakes need bemade to maintain the parts in operative condition and compensate for thenormal wear of the brake linings for a long )QIlOd and until the brakelevers assume ine cient angles, or until it becomes necessary to relinethe brakes. The distance which each of the movable actuator members, 1and 3, or 101 and 103, may move toward each other without bringing theminto contact, or in other words the strokes of the actuator members willbe sufiiciently great to compensate for the wear of both the front andrear wheel brakes for a long period and maintain the predeterminedpressures upon each, when applied, and compensate for the 1m equal wearof the linings or braking surfaces a of the front and rear wheel brakes.

Should the rear wheel brakes wear sufliciently to cause the foot pedalto reach the limit of its forward movement, usually determined by thepedal striking the floor board, before the said brakes are fullyapplied, it is only necessary to. take up or shorten the connection, 79,between the valve mechanism and the rear wheel brake mechanisms, whichcan be done very conveniently by rotating the wing nut, 79*, of theadjusting device, 79*, which in connection with the adjustable stop, 34,determines the release or oil' position of the rear wheel brakes. Thereleased positions for the front wheel brakes may e altered when desiredby means of the adjustable stop, 36, before described. It is obviousthat if the throw of the foot pedal were sufiiciently long or itsleverage connection with the brakes such that the throw of the pedal isas efiectively great as the combined movements of the parts, noadjustment would be necessary, but structurally, this is rarely found tobe practical in automotive vehicles.

it will be noted that in the constructions hereinbefore described, asboth of the power applying membersof the actuator are movable under thedifferential of fluid pressures, on their opposite faces we obtain twicethe power which would be obtained from-an actuator of the same size inwhich one oi said parts is rigidly connected to the chassis of thevehicle. This permits of the use of a smaller actuator than wouldotherwise be necessary, and less air would have to be exhausted from theactuator and delivered to the suction passage of the engine in effectingan application of the brakes, and there is, therefore, less danger ofinterfering with the operation of the engine or stalling it by the airexhausted from the power actuator.

What we claim and desire to secure by Letters Patent is 1. In a brakesystem for automotive vehicles provided with an internal combustionengine having a throttle controlled suction passage, the combinationwith a pair of steering wheel brake mechanisms, and a pairofnon-steering wheel brake mechanisms, ot a power'actuator comprising apair of power applying members capable of movement with respect tothevehicle and each other, and a bellows member in sealing engagementwith said members, connections from one of said members to the steeringwheel brake mechanisms, connections from the other of said members tothe non-steering wheel members, controlling valve mecha-- nism, meansfor connecting the interior of said bellows member with said suctionpassage and with the atmosphere under the control of said valvemechanism, and a hysically operable part, for operating an valvemechanism, operatively connected with the non-steering wheel brakemechanism.

2. In a brake system for automotive vehicles provided with an internalcombustion engine having a throttle controlled suction passage, thecombination with a pair of steering wheel brake mechanisms, and a pairof non-steering wheel brake mechanisms, of a power actuator comprising apair of power applying members capable of movement with respect to thevehicle and each other, and a bellows member in sealing engagement withsaid members, connections from one of said members to the steering wheelbrake mechanisms, connections from the other of said members to thenon-steering wheel members, controlling valve mechanisms, means forconnecting the interior of said bellows member with said suction passageand with the atmosphere under the control of said valve mechanism, and aphysically operable part, said valve mechanism comprising relativelymovable parts having a limited movement with respect to each other,connections from said physically operable part to one of said valveparts, and. connections from the other of said valve parts to thenon-steering wheel brake mechanisms.

3. In a brake system for automotive vehicles provided with an internalcombustion engine having a throttle controlled suction passage, thecombination with a pair of steering wheel brake mechanisms, and a pairof non-steering wheel brake mechanisms, of a power actuator comprising apair of power applying members capable of movement with respect to thevehicle and each other; and a bellows member in sealing engagement withsaid members, connections from one of said members to the steering wheelbrake mechanisms, connections from the other of said members to thenon-steering wheel members,

controlling valve mechanism, means for connecting the interior of saidbellows member with said suction passage and with the atmos here underthe control of said valve mec anism, and a physically operable part foroperating said valve mechanism, operatively connected with thenon-steering wheel brake mechanism, and a single adjusting device in theconnections between the physically operable part and the non-steeringwheel brake mechanisms.

4. In a brake system for automotive vehicles provided with an internalcombustion engine having a throttle controlled suction passage, thecombination with a pair of steering wheel brake mechanisms, and a pairof non-steering wheel brake mechanisms, of a power actuator comprising apair of power applying members capable of movement with respect to thevehicle and each other, and a bellows member in sealing engagement withsaid members, connections from one of said members to the steering wheelbrake mechanisms, connections from. the other of said members to thenon-steering wheel members, controlling valve mechanism, means forconnecting the interior of said bellows member with said suction passageand with the atmosphere under the control of said valve mechanism, and aphysio lily operable part, said valve mechanism comprising relativelymovable parts having a limited movement with respect to each other,connections from said physically operable part to one of said valveparts, and connec tions from the other of said valve parts to thenon-steerin wheel brake mechanisms, and a single achusting device if.the connections between the non-steering Wheel brake mechanisms and thevalve part connected therewith.

5. In a brake system for automotive vehicles provided with an internalcombustion engine having a throttle controlled suction passage, thecombination with a pair of steering wheel brake mechanisms, and a pairof non-steering wheel brake mechanisms, of

a power actuator comprising a pair of power applying members capable ofmovement with respect to the vehicle and each other, and a bellowsmember in sealing engagement .with said members, connections from one ofsaid members to the steering Wheel brake mechanisms, connections fromthe other of said members to the non-steering wheel members, controllingvalve. mechanism, means for connecting the interior of said bellowsmember with said suction passage and with the atmosphere under thecontrol. of said valve mechanism, and. a physically operable part foroperating said valve mechanism, operative y connected with thenon-steering wheel brake mechanism, and stops for engagin parts of thesaid respective connectlons irom the actuator to the brake mechanismsfor the steering and nonsteerin wheels to limit the return movement 0said connections to released position.

6. In a brake system for automotive vehicles provided with an internalcombustion engine having a throttle controlled suction passage, thecombination with a pair of steering wheel brake mechanisms and a pair ofnon-steering wheel brake mechanisms, of a power actuator comprising apair of power applying members capable of movement with respect to thevehicle and each other, and a bellows member in'sealing engagement withsaid members, connections from one of said members to the steering wheelbrake mechanisms, connections from the other of said members to the nonsteering wheel members, controlling valve mechanism, means forconnecting the interior of said bellows member with said suction passageand with the atmosphere under the control of said valve mechanism, and aphysically operable part, said valve mechanism comprising relativelymovable parts having a limited movement with res ect to each other,connections from said p ysically operable part to one of said valveparts, and connections from the other of said valve parts to thenon-steering wheel brake mechanisms, and a single adjusting device inthe connections between the non-steering Wheel brake mechanisms and theValve part connected therewith, and stops for engaging parts of the saidrespective connections from the actuator to the brake mechanisms forsteering and non-steering wheels to limit the return movement of saidconnections to released position.

CALEB BRAG'G.

VICTGR W. KLIESRATH,

